Stock 1.8 head flow numbers??

[type411]

Gert Hack talkes about friction or resistans and that you must reduce that by lowering the airspeed at the space you have to work with. It is a bit hard for me to explain, as I am doing this in a forean language. Sorry.
It lookes to me like the germans i the 70´s were fixed on lowering airspeed at the valve to reduce the los there. That could also be why they always want to put in very large valves.
Does this mean that you would use 45* intake on a othervice stock type4 engine. Or should I stay with the 30* intake seats ?

I cannot log into Jakes forums. Yes some of them. But most are "private" so I gues they are secret.

No the 2L 914 heads have 45* on the intake and the 1700, 1800 and 2L bus 30*

[fusername]

you need to register for a lot of jakes stuff.

[Rolf]

you need to register for a lot of jakes stuff.

Type411 have registered to Jake's forum, it just looks like he's not approved by Jake. Can't think of any reason why type411 should'nt be allowed access to Jake's forums. Looks like Jake have lost interest in his type 4 forum.

/Rolf

[Piledriver]

It can take awhile, and sometimes you have to be a bit persistent.

IIRC, Jake was getting hammered recently by spambots trying to register (hundreds a day)... He actually had to shut off all new registrations for a while.

[fusername]

oh, I misunderstood. don't feel bad type411, I still can't view pictures on his forums...

[type411]

I don`t feel bad. It is his los. But thanks anyway.

[HAM Inc]

Mixture velocity needs to drop some so the mixture can distribute evenly to the backside of the valve, which is critical for max flow between the valve and seat, which is critical for max mixture quality. This is the primary reason for enlarging the bowl area beneath the valve.

The shape and size of the bowl area in relation to the size and profile of the valve and seat is very critical. There has possibly been more R&D in this area than any other of the ICE. I know I spend a lot of time in there. There are so many factors that go into a proper combo of these specs that endless experimentation is possible. Change the valve profile and you need to change the seat profile which leads to a need to optimize the bowl area for the new specifications. And we mustn't forget that the first half inch or so of the combustion chamber area around the valve is actually an extension of the port itsef, so changes there can effect the shape requirements below the valve.
It is well documented that the 1/2" below the intake valve seat, the seat itself and the 1/'2" above the seat is the most critical area of the entire engine for max power. Blow it there and nothing you do anywhere else will make up for it. Get it right, and many other sins can be forgiven and fixed as tuning goes along.

BTW, Jakes forum is well worth the effort to get access. Lots of great discussions over there!

[type411]

Where are Jakes socalled "super stock" head (42/36) compared to the stock 412S head (41/34) ?

[HAM Inc]

These #'s are old and a bit lower than the current 7424 (AKA Super Stock)) heads, but not by a lot. I don't have the latest flow #'s on my office PC so these will have to do until I can transfer them from the flowbench computor.

0.0500 27.2 29.9 28.00 28.00
0.1000 51.3 58.1 28.00 28.00
0.1500 72.0 84.9 28.00 28.00
0.2000 87.8 110.8 28.00 28.00
0.2500 98.8 130.2 28.00 28.00
0.3000 107.5 139.1 28.00 28.00
0.3500 113.8 146.4 28.00 28.00
0.4000 118.4 156.0 28.00 28.00
0.4500 122.9 164.7 28.00 28.00
0.5000 123.9 172.0 28.00 28.00

[type411]

Ok thanks.
It must mean that a 7416 is just as good or a little better than the stock 412S.

[63busguy]

Looking for stock port volumes, chamber cc, step height if any for VW 1.7, 1.8, 2.0, 412S and Porsche 2.0.

If possible chamber cc separate from the step volume.

Thanks in advance!

Also any flow numbers for out of the box AMC heads with the above cc information would be great!

[Piledriver]

The step was not there from the factory.
Shows they were reworked.
The step cut is not always helpful, or always bad, depends on what you are building.
It does need to be "designed in" (accounted for) if present.

1.7/1.8/2L bus & AMC~55-58cc
2.0 Porsche ~65cc, give or take 2-3.
Unmolested heads, YMMV.

The step if present is measured just like deck volume, as that's what it is.

[63busguy]

Thanks again!

Any idea what stock combustion chamber volumes are?

[Piledriver]

Thanks again!

Any idea what stock combustion chamber volumes are?

...
1.7/1.8/2L bus & AMC~55-58cc
2.0 Porsche ~65cc, give or take 2-3.
Unmolested heads, YMMV.

[63busguy]

Sorry I thought those were intake port volumes.

Have the intake port volume numbers by any chance?